Research Project: Nutritional Benefits of Health-Promoting Rice and Value-Added Foods

Location: Food Processing and Sensory Quality Research

2023 Annual Report

Objectives
1. Develop commercially viable processing technologies that produce health-promoting foods from whole grain rice and rice co-products. [NP306, C1, PS1A, 1B] (S. Boue, J. Beaulieu) 1.1. In this sub-objective research will characterize different rice processing techniques with emphasis on increasing health-promoting rice components (phytonutrients). Processing will include different cooking methods of table rice, parboiling, drum drying and extrusion of rice co-products. 1.2. Establish temporal boundaries during sprouting between de novo synthesis of health-beneficial phytonutrient compounds versus catabolic loss or change in macronutrients. 2. Enable commercial uses of whole grain rice and other crops as sprouts and microgreens in value-added foods and functional products. [NP306, C1, PS1B, 1C] (J. Beaulieu, S. Boue, Vacant - Sensory Scientist) 2.1. Develop value-added products (e.g. beverages, powders, flours) from select, optimized, sprouted colored bran rice and grain varieties, and commercially important sprouted crops. 2.2. Rice flour enriched with phytonutrients by sprouting and resistant starch by processing (from Sub-Objective 1.1) will be utilized as an ingredient in several rice functional foods.

Approach
Brown and colored rice will be analyzed using different cooking methods to determine methods to produce resistant starch and determine health benefits. Several processing methods will require rice to be milled to a flour. Rice processing methods and assays (in vitro and in vivo) to produce resistant starch and determine health benefits: Measurement of starch types will be conducted and compared to other starch sources. An in vitro fermentation system will be utilized to determine the effects of rice and rice ingredients on gut health. Research at the SRRC will germinate several rice varieties, including sprouted germinated brown rice, high protein rice and colored rice. Green technologies will deliver a free-flowing germinated brown rice beverage, with limited GRAS additions. A process developed at the SRRC has created the foundation for preliminary germinated brown rice beverages. Rice flour that is enhanced with resistant starch and polyphenolics from sprouted rice will be extruded into foods and analyzed for bioactive and phytonutrient content. Rice flour without added resistant starch and not sprouted will be the control. A sensory panel will determine if flavor and texture are comparable to foods produced from commercially available rice flour.

Progress Report
Due to critical vacancies, milestone progress has been slow but is progressing. Due to retirement, the unit currently does not have a pilot plant operator. Additionally, this project is currently operating with two critical scientist vacancies. Milestones not met from FY 2022 are now substantially met or complete. These milestones include, “Complete parboiling and drum drying of rice to enhance resistant starch in rice,” and “Completed green technologies method to produce value-added germinated brown rice beverage with key GRAS additives.” For Objective 1, ARS scientist in New Orleans, Louisiana have been continuing to sprout rice varieties that could have added value when used in foods. Varieties of commercially available brown, purple, and red rice were sprouted. Researchers are now evaluating total phenolic content and g-aminobutyric acid content over a 72-hour germination period. FPSQ has also acquired a new extruder to produce resistant starch in food products made from rice flour. Furthermore, ARS scientists created an experimental rice parboiling apparatus and are investigating the effects of parboiling colored rice varieties. In support of Objective 2, in FY22, ARS scientists developed acidified cold-brewed sorghum bran beverages as a model system for planned rice bran beverage research and development. At that time, ARS researchers analyzed bran and beverages for total phenolic content & profile, antioxidant capacity, condensed tannins, and proximate composition. Additionally, they conducted a sensory study with 112 consumers to evaluate acceptability of sensory attributes and purchase intent before and after providing an antioxidant message. Since this time, scientists from ARS have acquired the necessary equipment to manufacture rice bran similar to the sorghum bran used as a model system. They made significant progress in creating rice bran beverages with optimal phenolic content, texture, consistency, mouthfeel, and particle suspension. They have started preliminary sensory tests. Also in support of Objective 2 ARS researchers recently developed ricemilk prototypes using white, brown, red, and purple aromatic rices which mimic properties of commercial ricemilk, but with potential added health benefits and unique sensory profiles. FPSQ scientists are using these formulations as vehicles to incorporate sprouted rice into value-added food products and to collect human sensory data on products made from pigmented and sprouted rice. The FPSQ sensory laboratory recruited an intern from Montclair State University to participate in this project. Researchers have measured total phenolic content and preliminary sensory tests are being conducted. In support of Objective 2, substantial progress has been made in FY2023 developing lexicons (standard vocabulary used to describe products) for white, brown, red, and purple rice varieties to describe consumers’ sensory, emotional, and wellness perceptions. They are using a modified individual sample description technique through visual evaluation of rice samples and photographs to generate initial lexicons. An online survey will further refine the lexicons to relevant terms. Scientists will also analyze perceived quality and healthfulness based on appearances. This information can help rice processors and breeders identify target consumers as well as aid product development and potential marketing strategies for new types of rice in the U.S. Also in support of Objective 2, scientists from the ARS have studied and identified rice hulls that contain phytoalexins with certain biological activities, including estrogenic activity. These plant-based estrogens can provide benefits to reproductive health, heart health, weight loss management, hormone-influenced tumor prevention, bone and skin health, as well as immune system enhancement. They are currently investigating the potential biological activities of these substances due to their flavonoid and terpenoid components. Lastly, soybean seeds and sprouts exposed to stress have been tested for the production of phytoalexins such as glyceollins, with extracts obtained from these plants being evaluated for possible biological effects on various cell assays. ARS scientists made progress in the agreement (No. 6054-41000-112-003S) with Tulane University and agreement (No. 6054-41000-112-005S) with Xavier University. USDA scientists are utilizing rice sprouts from various brown and pigmented rice varieties to generate phytoalexins, which are antimicrobial compounds that some plants create to defend against pathogens. Analysis has identified flavonoid and terpenoid components within the sprouts. ARS researchers are now assessing both elements for biological activity. Moreover, soybean seeds and sprouts have been stressed to create phytoalexins like glyceollins that have proven health-promoting effects. ARS scientists are examining plant extracts and individual components for potential health benefits in collaboration with Tulane and Xavier Universities researchers who have employed both 2D-cell and 3D-organoid systems to investigate how these extracts and individual compounds can benefit human health. Tulane and Xavier Universities are providing updates through quarterly reports while ARS researchers evaluate soybean flour containing glyceollins for its potential health advantages in multiple studies.

Accomplishments
1. Cereal bran enhances fiber content and antioxidants in gluten-free bread without compromising quality. Gluten-free products often lack nutrients like fiber and can have diminished sensory quality. Sorghum and rice brans contain both fiber and antioxidants without gluten. ARS scientists at New Orleans, Louisiana, and Manhattan, Kansas, produced an optimized gluten-free bread containing 14.3% sorghum bran. The scientist tested the bread’s physical and chemical properties and conducted a sensory test with 100 consumers. The optimized bread was “high in fiber” and demonstrated antioxidant activity without compromising sensory quality. The study received media attention including a Food Technology magazine article, an ARS news article, and an interview featured on the Omnivore podcast. Optimization techniques can also be used with health-promoting rice brans. This research is important to gluten-free consumers who must avoid gluten and those who seek a healthy lifestyle. This research is also important to rice growers and processors as it may provide a means to add value to rice bran, a major byproduct of rice processing.

2. Underutilized cereal brans provide antioxidant capability to novel beverages. Rice and sorghum brans contain polyphenolic compounds with health-promoting effects, but the bran layers are removed from grains during milling and are associated with bitter taste. ARS scientists at New Orleans, Louisiana, in collaboration with ARS researchers at Manhattan, Kansas, used sumac sorghum bran to produce novel acidified beverages, as a model system for rice bran. For this, ARS scientists evaluated in vitro antioxidant activity and consumers’ perceptions of the products. Beverages showed measurable antioxidant capacity. Adding sweetness decreased bitter taste and increased acceptance. Additionally, consumers’ intent to purchase the beverages increased after antioxidant messaging. This study demonstrated proof-of-concept for a first-of-its kind cold-brewed bran beverage. This work will serve as a benchmark for development of novel rice bran beverages, which can add value to byproducts and enhance utilization of healthy grain components. This research is also important to rice growers and processors as it may provide a means to add value to rice bran, a major byproduct of rice processing.

3. Elderly individuals with obesity benefit from consuming soybean products. Scientists at the Pennington Research Center, in collaboration with ARS scientists at New Orleans, Louisiana, conducted a dose-escalating clinical trial to assess the safety and tolerability of soybean products in eight elderly individuals between 70 and 85 years old who had obesity. The scientists processed whole green soybean pods into flour and incorporated it into foods. They found that 30 grams of whole soybean flour was well-tolerated and made participants feel satiated. The scientists also produced a second food item using mature soybean seeds which had been subjected to stress in order to boost the level of glyceollins. Results also demonstrated the reduction of oligosaccharides, which in turn decreased flatulence. Providing soybean flour at <30 g/day may be prudent for overall health in older adults with obesity. Whole soybean foods with glyceollins are being considered in several studies to improve health.

Review Publications
Sadeghi, R., Colle, M., Smith, B. 2023. Protein composition of pulses and their protein isolates from different sources and in different isolation pH using a reverse phase high performance chromatography method. Food Chemistry. 409. Article 135278. https://doi.org/10.1016/j.foodchem.2022.135278.
Yazar, G., Kokini, J., Smith, B. 2023. Comparison of mixing and non-linear viscoelastic properties of carob germ glutelins and wheat glutenin. Food Hydrocolloids. 143 Article 108922. https://doi.org/10.1016/j.foodhyd.2023.108922.
Ardoin, R., Smith, B., Bean, S., Aramouni, F. 2023. Optimization of tannin containing sorghum bran addition to gluten-free bread. Journal of Food Science. 88(3):952-961. https://doi.org/10.1111/1750-3841.16477.
Ardoin, R.P., Smith, B., Lea, J.M., Boue, S.M., Smolensky, D., Santana, A.L., Peterson, J.M. 2023. Consumer perceptions and antioxidant profiling of acidified cold-brewed sorghum bran beverages. Journal of Food Science. 88(6):2301-2312. https://doi.org/10.1111/1750-3841.16589.
Rebello, C., Boue, S.M., Levy, R., Puyau, R., Beyl, R., Greenway, F., Heiman, M., Keller, J., Reynolds, C., Kirwan, J. 2023. Safety and tolerability of whole soybean products: A dose-escalating clinical trial in older adults with obesity. Nutrients. 15(8):1920. https://doi.org/10.3390/nu15081920.
Patel, J., Banjara, B., Ohemeng, A., Davidson, M.A., Boue, S.M., Burrow, M., Tilghman, S. 2023. Novel therapeutic combination targets the growth of letrozole resistant breast cancer through decreased cyclin B1. Nutrients. 15:1632. https://doi.org/10.3390/nu15071632.
Walker, R., Patel, J., Davidson, M.A., Williams, C., Payton-Stewart, F., Boue, S.M., Burow, M., Tilghman, S. 2022. Glyceollin triggers anti-proliferative effects in hormone dependent aromatase inhibitor resistant breast cancer cells through the induction of apoptosis. International Journal of Molecular Sciences. 23. Article 2887. https://doi.org/10.3390/ijms23052887.
Gharibzahedi, S.M.T., Smith, B., Altintas, Z. 2022. Bioactive and health-promoting properties of enzymatic hydrolysates of legume proteins: A review. Critical Reviews in Food Science and Nutrition. https://doi.org/10.1080/10408398.2022.2124399.